bliss



(No Model.)

J. BLISS. COMPENSATION BALANCE FOR TIMEPIEGES;

No. 492,184. Patented Feb; 21, 1893.

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Unrrn STATES PATENT JOHN BLISS, OF BROOKLYN, ASSIGNOR TO JOHN BLISS (it00., OF NElV YORK, N. Y.

COMPENSATION-BALANCE FOR TIMEPIECES.

SPECIFICATION forming part of Letters Iatent No. 492,184, dated February21, 1893.

Application filed June 1, 1892. Serial No. 43 5,166. (No model.)

To all whom it may concern.-

Be itknown that 1, JOHN BLIss, of Brooklyn, in the county of Kings andState of New York, have invented a new and useful Improvement inCompensation-Balances for Ohronometers and other Timepieces, of whichthe following is a specification.

When time pieces, such as marine chronometers and watches are fittedwith the ordinary form of compensation balance,viz: arms attached to thebalance staff, carrying at their outer ends laminated rims of differentmetals on which rims are fastened the compensation weights it is foundthe balance weights may be so adjusted that the daily rate of going willbe practically the same in any two eX- treme temperatures, say 30 and 90Fahrenheit. For ordinary watches and where strict accuracy is notnecessary it is assumed the daily rate is the same in all othertemperatures. But itis well known that in the intermediate temperatureof the daily rate will be faster by a quantity that varies in differentchronometers from about two seconds to four seconds per day. This error,called the intermediate or secondary error, is one which occasions greatinconvenience where it is desired to accurately carry forward time forlengthened periods, whether mean time for the purposes of navagation orstandard time for civil affairs or siderial time for astronomicalpurposes. This difficulty is usually met either by applying to theaccumulated error of the chroflometer a daily correction made up of therate in the mean temperature and the error from that rate due to themean temperature of each day, or by applying some kind of auxiliarycompensation for the purpose of overcoming the secondary error.

Many of the various forms of auxiliary compensation are highlyobjectionable for. the reason that they are complicated and expensive,do not retain their adjustment, add too much unnecessary weight to thebalance, are unstable and often produce worse errors than they areintended to counteract.

The object of the present invention is to obtain a device for eifectingthe compensation for the secondary error which is less complicated andexpensive, more easily adjusted, less liable to get out of adjustmentand more reliable in its action than the means heretofore employed forthe purpose.

I have said that the daily rate of a chronometer with an ordinarybalance is fasterin the intermediate temperature than in the extremes 30and Conversely, if the chronometer be regulated to go at mean time in'70 it will lose in any temperature higher or lower than 70. What isneeded then is that something shall counteract this natural tendency togo slower with a rise or fall of temperature.

I will proceed to describe my invention with reference to theaccompanying drawing which represents on a scale considerably largerthan the real size, a plan view of a chronometer balance to which theinvention is applied.

A A are the arms of the balance and B B are the two members into whichthe laminated rim is divided, one of said members being at tached nearone end to each arm. Each of said members has adj ustably secured uponit one of the compensation weights O O, and each has also fitted to itone of the timing screws D D. The parts so far described are common.

To provide for the auxiliary compensation for the secondary error Iattach to the inner face of either or each member of the laminated rimnear its free end one end of a thin spring E of steel or other elasticmaterial which is bent to reach over the unoccupied part of the armwhich carries the other member of the rim, and to the free end of saidspring so reaching over the arm I attach a small weight a Z), the innerend or face of which presented toward the axis of the balance is taperedto an edge or rounded or pointed to bear against a small pin d ofhardened steel or any other suitably hard material standing on the armperpendicular to the plane of the balance. The said weight a Z) is keptin contact with the pin d by the springE with sufficient force of thespring to overcome any tendency of the centrifugal force when in motionto cause any separation of the said weight and the pin. When the saidweight and the pin are of the right weight and diameter respectively,which are found by experiment and the point ofthe said weight isadjusted so that at the temperature of 70 it will rest on that portionof the pin farthest from the center of the balance, then any movementinward or outward of the laminated rim will permit the said weight tomove toward the center of the balance and cause the balance to movefaster just enough to counteract the loss by reason of the secondaryerror.

The spring E is represented as attached to the laminated rim by means ofscrews 6 e and the attached part is represented as provided with slotsff through which the fastening screws 6 e passinto the rim to provide ameans of adjusting the point or edge of the weight a b on the pin. Thisis shown at the right hand side of the drawing where the springE andweight a b and part of the laminated rim are shown in section. It isobvious however, that the pin (Z might be made adjustable across thebalance arm for the same purpose.

The weight a b may be constructed with its sharpedged, pointed orrounded face in any suitable manner. It is represented as consisting ofa screw a and nut l), the screw passing through the spring E and securedby the nut, the head of the screw being toward the axis of the balanceand having the sharpedged, pointed or rounded face which impinges uponthe pin (Z. The pin (Z may be attached to the laminated rim B and thespring E to the arm A or the adjoining rim B.

What I claim as my invention, and desire to secure by Letters Patent, is

The combination with a balance having a divided laminated rim, of aweight, a spring by which said weight is attached to the said rim andforced toward theaxis of the balance, and a pin carried by one of thearms of the balance to sustain said weight against the force of the saidspring, substantially as and for the purpose herein set forth.

JOHN BLISS.

Witnesses:

CHAS. A. HAVILAND, G. AUeUsTUs HAVILAND.

